Air passengers will be required to get a viral test within three days before their flight to the United States departs, and to provide written documentation of their lab results, or documentation of having recovered from Covid-19, the agency said in a statement to CNN.

CDC Director Dr. Robert Redfield is expected to sign the order on Tuesday and it will go into effect on January 26.

If a passenger does not provide documentation of a negative test or recovery, or chooses not to take a test, the airline must not allow the passenger to board, the CDC said.